#!/bin/python
#_*_coding=utf-8_*_
def yunsuan(userA,userB,operate):
    '运算函数'
    try:
        A = int(userA)
        B = int(userB)
        operate_list = { '+':(A+B),'-':(A-B),'*':(A * B),'/':(A / B)}
        return operate_list[operate]
    except KeyError:


        return '%s 没有这个运算' % operate

    except ValueError:


        return '请给我个数字！'
    except ZeroDivisionError:

        return '%s 不能为除数！' % userB

def user_input():
    '获取用户输入'
    userA = raw_input('请输入数字A: ')
    userB = raw_input('请输入数字B: ')
    operate = raw_input('请选择运算符号(+、-、*、/)：')


    return yunsuan(userA,userB,operate)
print user_input()